This invention relates to bearing assembly machines with the preferred embodiment disclosed herein being of a needle bearing assembly machine for assembling a double row of needles into a pinion.
Bearing assembly machines are complicated pieces of equipment which automatically assemble a number of individual bearing elements to a retainer to form a bearing assembly. One type of bearing assembly which may be assembled by a bearing assembly machine comprises an annular retainer member into which a plurality of individual bearing needles are assembled in a circular array. The specific type of bearing assembly which is assembled by the bearing assembly machine disclosed in the present patent application is a pinion assembly comprising an annular pinion member into which two circular rows of bearing needles are assembled with the two rows being separated by an annular spacer element.
Because bearing assemblies are basically precision articles of manufacture, the requirements imposed on a bearing assembly machine are rather demanding. A bearing assembly machine must be capable of attaining precision assembly of the bearings, and in doing so it must handle a very large number of individual components rapidly and without damaging the components. A typical bearing assembly, regardless of its type, will normally comprise a large number of individual bearing elements. For example, in the bearing assembly which is disclosed in the present application, the two rows of bearing needles may each contain on the order of twenty individual needles. Accordingly, a single bearing assembly, including the spacer ring and the pinion, involves the assembly of forty-some individual components into a precision assembly. Moreover, in order to be cost-effective, a bearing assembly machine must be capable of a high production rate with its cycle time involving merely a few seconds. Given the assembly steps which are required for the typical bearing assembly, one can appreciate that a bearing assembly machine must comprise a number of rapidly moving machine elements which must be operated in extremely close synchronism.
Prior bearing assembly machines have used camshafts containing a number of individual cams for controlling individual machine elements. The cams contain tracks in which cam followers are captured. The followers are coupled via linkages with the machine elements which perform the assembly operations. Examples of these types of bearing assembly machines are shown in U.S. Pat. No. 2,057,692. One problem with this prior type of machine arises because the cam followers are captured within the cam tracks. Because the captured cam followers are constrained to follow their respective cam tracks, a jam during machine cycling can give rise to serious problems. A jam may be especially difficult to clear. Damage to the machine mechanism may have occurred and/or intentional mechanical disconnect devices, such as shear pins and the like, may have been activated. Obviously, where the machine components have been damaged they must be repaired and/or replaced, and where a disconnect device has been actuated it must be either replaced or reset. The resulting downtime impairs the overall efficiency of the machine. It may be necessary to reset the machine in order to establish the correct timing synchronization between the various assembly elements of the machine. These prior cam-actuated machines have a further disadvantage in that it is difficult to control the assembly forces. Because captured cam followers tend to impart definite forces to the machine elements which they control, mechanical springs are used to compensate those forces, where such compensation is necessary. The springs themselves are subject to tolerance and when cycled at the high rates which are demanded in a bearing assembly machine can present problems.
The present invention is directed to a new and improved bearing assembly machine which overcomes disadvantages of prior bearing assembly machines. With the present invention, and likelihood of jamming is reduced, and even if a jam occurs, the likelihood of damage to the machine is significantly reduced. Any jams which may occur can be cleared more rapidly and the amount of downtime is less. Assembly forces may be more accurately controlled and power efficiency is improved. A further, and very significant attribute of the invention is that productivity is dramatically increased over that obtainable with prior machines. For example, production rates of 1200 assemblies per hour or more are achievable with the present invention.
The foregoing features, advantages, and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a preferred embodiment of the invention in accordance with the best mode contemplated at the present time for carrying out the invention.